Liquid Filtering Device

ABSTRACT

A filter arrangement for liquids has a filter housing and a functional carrier arranged inside the filter housing. A cylindrical filter element is inserted axially into the filter housing and defines an unfiltered side and a filtered side inside the filter housing. A non-return diaphragm is secured within the filter housing, wherein the non-return diaphragm is arranged on the functional carrier so as to effect an axial and/or radial sealing action of the unfiltered side relative to the filtered side of the filter arrangement.

TECHNICAL FIELD

The invention relates to a filtering arrangement for liquids, in particular for oil or fuel of an internal combustion engine, according to the preamble of the independent claim.

PRIOR ART

Filter elements for liquid filtration of viscous media such as oil or fuel are produced in a conventional way from pleated filter media preferably in a cylindrical shape. These filter elements can be free of metal and can be provided with an end plate of film, cardboard, plastic material, for example, PA, or something similar. Embodiments with metal end plates and a central metal tube are possible also. In this connection, the pleats of the filter elements are often incorporated into the end plates, for example, glued, welded, or foamed, and directly connect these elements.

The embodiments comprising a central tube for receiving the filter elements are often designed such that a reciprocal sealing action of the unfiltered side and the filtered side in the flow of the medium to be filtered is realized by means of an O-ring that is pushed onto the central tube; the O-ring is then exchangeable during servicing.

It is disclosed, for example, in DE 100 46 494 A1 to employ a metal-free filter element in an oil filter for filtering oil of an internal combustion engine. This filter element is inserted into a housing and the housing is closed off by a lid. In the housing, for reducing oil return upon shut-down of the internal combustion engine, a non-return vale is usually provided. In this connection, at least one seal is arranged on the filter element such that it rests seal-tightly against a housing wall of the filter housing within a predetermined axial movement area.

For preventing the filter housing from draining completely in the tube direction, it is also customary to employ a spring-loaded valve that is permanently introduced into the housing. These non-return valves are inserted in a separate assembly step into the housing and the non-return valves are comprised usually of a valve plate that is pre-tensioned by a spring; a valve crown; and a valve seat. The valve is screwed into the housing or inserted, wherein, generally, it is disadvantageous that assembly of this module is complex.

For example, DE 42 40 656 C2 disclose a further filtering arrangement for fuel and/or lubricants of an internal combustion engine in which a bottom drainage is provided that is closed off by an end plate of the filter element upon insertion of the filter element. This drainage is opened as soon as the filter element is removed so that the oil can flow out through this drainage bore into a catch basin. Also known in the prior art is a non-return valve that is comprised of a metal plate that is loaded by a spring and that seals the supply bore for the unfiltered oil. In this connection, different valve components are required.

Moreover, U.S. Pat. No. 5,413,712 discloses a filter for liquids in which the end plates of the cylindrical filter element are made from plastic material that is connected to the filter element. As a non-return diaphragm, an additional radially sealing rubber diaphragm is provided that rests against the end plate and is inserted during assembly.

DISCLOSURE OF THE INVENTION

The invention has the object to further develop a filter arrangement according to the preamble of the independent claim in a simple way such that a non-return valve can be produced and mounted in the filter housing in a simple way.

The filter arrangement for liquids in accordance with the invention has according to the preamble a cylindrical filter element that is insertable axially into the filter housing, wherein the filter element after mounting effects closure of a return device for the unfiltered liquid that is to be filtered with at least one seal secured on the filter element acting as a non-return diaphragm. In an advantageous way, the filter arrangement according to the invention is designed such that the non-return diaphragm is mounted on a functional carrier of the filter arrangement in such a way that an axial and/or radial sealing action of the unfiltered side and filtered side of the filter arrangement is effected.

The liquids to be filtered can be, for example, fuel and/or lubricants for an internal combustion engine in a motor vehicle, but also water. Preferably, the non-return diaphragm can be mounted on an axial projection of the functional carrier in such a way that a flexible contact of the non-return diaphragm on the sealing surfaces of the filter arrangement results within axially predetermined limits.

In an especially advantageous way, the axial projection of the functional carrier is dimensioned such that by means of the projection, upon contacting a step of the filter housing, a stop is provided. By means of an advantageous size of the length of the projection, after insertion of the filter element and hitting the step, a predetermined pretension of the non-return diaphragm resting against the sealing surface can be effected by the remaining space allowing a flexible deformation of the diaphragm.

Moreover, according to another advantageous embodiment, the functional carrier can be an end plate that is fixedly connected to the filter element, wherein the non-return diaphragm is attached to the end plate and wherein the end plate is designed such that radial noses are provided on it that laterally engage matching recesses of the filter housing, wherein the recesses in this connection are also sized such that with the recesses when contacted by the radial noses a stop is formed so that by means of the remaining space a predetermined pretension can be generated when the diaphragm rests against the sealing surface of the filter housing.

With the aforementioned embodiment, correct mounting can be ensured because in this way it is made sure that the pretension of the non-return diaphragm is not too great, that the filter element as a result of the stop does not sag downwardly, and that an incorrectly mounted filter element is pushed onto its seal seat.

It can be especially advantageous when the functional carrier has a metal-free central tube fixedly connected to the filter element to which the non-return diaphragm is seal-tightly attached. On the central tube in a simple way a diaphragm, for example, made from elastomer, is mounted that prevents that the filter housing will run empty in certain mounting situations. The diaphragm is designed such that it acts as a radial or axial seal between the unfiltered and filtered sides with a corresponding projection of the filter housing. The non-return diaphragm is exchangeable in this embodiment and is exchanged together with the filter element.

According to another advantageous embodiment the functional carrier is a central tube that is metal-free and is mounted fixedly in the housing of the filter arrangement, wherein the non-return diaphragm is fixedly connected to the tube. In this connection, the embodiment of the central tube must however be such that the filter element can be removed in a direction toward the lid. For this purpose, the diaphragm must be made of a material, for example, an appropriate elastomer, that is permanent and matched to the service life of the vehicle. The material of the central tube can be selected within limits but should be completely incineratable so that in this connection in particular plastic materials such PA, PP, PE, POM, PUR or comparable materials are advantageous.

In an advantageous way, the functional carrier can also be an end plate that is fixedly connected to the filter element and to which the diaphragm is attached. However, in many applications it is also very advantageous when the functional support has an end plate that is connected by means of a snap-on connection to the filter element to which end plate the non-return diaphragm is attached. In this connection, when snapping on or axially pushing the end plate against the end faces of the filter element radial snap-on noses can engage laterally the intermediate spaces of the folded filter webs of the filter element above the axial glued connection of the filter webs and provide a detachable connection in this way. In this connection, elastomer extensions of the non-return diaphragm that are secured on the functional carrier can be clamped radially and/or axially between the functional carrier in the filter element for sealing purposes.

Such a component that is composed of the non-return diaphragm and the functional carrier can be pre-manufactured in a simple way independent of the filter element and can be attached by simple manipulations and optionally can also be removed once the filter element is mounted.

The non-return diaphragm in all afore described embodiments can be connected fixedly to the functional carrier by gluing, welding, or by means of a two-component method. Alternatively, a detachable connection of the non-return diaphragm with the functional carrier by coupling can be provided.

As a result of the space-saving embodiment of a valve as a non-return diaphragm in accordance with the invention, the filter housing can be very compact. The non-return diaphragm can be produced and mounted inexpensively and is therefore less expensive than a spring-loaded cup valve in accordance with the prior art. The non-return diaphragm according to the invention can be embodied as a shaped part and, in an advantageous way, can take over the sealing function of an O-ring as a seal for the otherwise required sealing action between the unfiltered side and filtered side of the filter arrangement so that this element can also be eliminated.

BRIEF DESCRIPTION OF THE DRAWINGS

Embodiments of the filter arrangement according to the invention will be explained with the aid of the Figures. It is shown in:

FIG. 1 a section of a basic configuration of a filter arrangement for liquids according to the prior art;

FIG. 2 a a schematic illustration of a filter element for a filter arrangement according to FIG. 1 with a non-return diaphragm and an axial sealing action of the unfiltered side in the liquid flow;

FIG. 2 b a schematic illustration of a filter element for a filter arrangement according to FIG. 1 with a non-return diaphragm and a radial sealing action of the unfiltered side in the liquid flow;

FIG. 3 a a detail illustration of a radially sealing non-return diaphragm with a two-component attachment on an end plate of the filter element;

FIG. 3 b a detail view of an axially sealing non-return diaphragm with a two-component attachment on an end plate of the filter element;

FIG. 3 c a detail illustration of a radially sealing non-return diaphragm that is coupled to an end plate of the filter element;

FIG. 3 d a detail view of an axially sealing non-return diaphragm that is coupled to an end plate of the filter element;

FIG. 3 e a detail illustration of another embodiment of an axially sealing non-return diaphragm that is connected to an end plate of the filter element;

FIG. 4 a schematic illustration of an axially sealing non-return diaphragm that is mounted on a two-part snapped-on central tube for a filter element;

FIG. 5 a schematic illustration of an axially sealing non-return diaphragm that is mounted on a single-part central tube for a filter element;

FIG. 6 a schematic illustration of a radially sealing non-return diaphragm that is mounted on a single-part central tube for a filter element;

FIG. 7 a further schematic illustration of a non-return diaphragm that is mounted on an extended central tube for a filter element;

FIGS. 8 a to 8 c further embodiments of attachments of the non-return diaphragm on the central tube according to FIG. 7;

FIG. 9 an embodiment of an end plate on the filter element that has a stop for generating a defined pretension for the non-return diaphragm;

FIG. 10 an embodiment that has an end plate with a non-return diaphragm and can be attached to the filter element by means of a snap-on connection;

FIG. 11 a plan view of one embodiment of an end plate with radial noses.

EMBODIMENT(S) OF THE INVENTION

In FIG. 1 a filter arrangement is illustrated that, in principle, corresponds to a filter arrangement for fuel or lubricant for an internal combustion engine disclosed in the prior art reference DE 100 46 494 A1. The unfiltered liquid that is to be filtered flows through an inlet 1 into the filter housing that is comprised of a top part 2 and a bottom part 3. In the filter housing, a filter element 4 of zigzag-folded filter paper is arranged that is pushed onto a central tube 5 and is clamped fixedly upon joining the filter housing. The unfiltered liquid flows through the filter element 4 and exits at the filtered side through the central tube 5 and through the outlet 6.

A non-return diaphragm 7, for example, made of elastomer, is arranged on the end plate 8 of the filter element 4 and releases at the unfiltered side the liquid flow but upon interruption of the flow, for example, when the internal combustion engine is shut down, prevents return flow into the supply channel 1 as the diaphragm contacts axially or radially the filter housing. FIGS. 2 a and 2 b illustrate the principal mechanisms of the function of such non-return diaphragms 7; FIG. 2 a shows an axial sealing action and FIG. 2 b shows a radial sealing action.

FIGS. 3 a to 3 e show respectively different embodiments of the non-return diaphragm 7 mounted on an end plate 8. The FIGS. 3 a and 3 b show non-return diaphragms 7 that are glued, welded or connected by a two-component method, and FIGS. 3 c to 3 e show non-return diaphragms 7 coupled to the end plate 8.

FIG. 4 shows the attachment of the non-return diaphragm 7 on a two-part central tube 5, and FIG. 5 and FIG. 6 show, respectively, an attachment of the non-return diaphragm 7 on a single-part central tube 5.

FIG. 7 shows an embodiment in which the non-return diaphragm 7 is attached to the central tube 5 in such a way that a sealing bead 9 results with which a radial sealing action between the central tube 5 and the bottom housing part 3 (compare FIG. 1) can be realized. FIG. 8 a shows the possibility of an axial sealing action with the sealing bead 9, and FIGS. 8 b and 8 c show further sealing actions as a supplement to the arrangement according to FIG. 7.

In FIG. 9, as a supplement to the illustrations of FIGS. 3 a to 3 c, it is shown that for an end plate 8 as a functional carrier a non-return diaphragm 10 can be attached to the end plate 9 and in particular to a projection in the form of an axial projection 11 of the end plate 8. This area of the end plate 8 is embedded by injection-molding with an elastomer for forming the non-return diaphragm 10 wherein, in this connection, a radial seal 12 for sealing relative to an inner sealing pin 13 can be integrated. The axial projection 11 is sized with regard to its length such that by means of it upon contacting the step 14 of the filter housing a stop is formed so that as a result of the remaining space (arrow 15) a predetermined pretension can be produced when the non-return diaphragm 10 contacts the sealing surface of the filter housing.

FIG. 10 shows an alternative embodiment of an end plate 16 as a functional carrier having on the exterior so-called snap-on noses 17 so that the non-return diaphragm 10 with the end plate 16 can be connected by means of a snap connection to the filter element 4. Upon snapping on or upon axial sliding onto the end surface of the filter element 4, the snap-on noses 17 engage laterally the intermediate spaces of the folded filter webs of the filter element 4 above an axial glued connection 18 of the filter webs and provide a detachable connection in this way.

In this connection, it is also possible to provide by injection molding elastomer extensions on the non-return diaphragm 10 radially and/or axially between the end plate 16, 17 and the filter element 4 that, for providing a sealing action, are clamped during mounting.

An end plate 20 according to FIG. 11 is designed such that, as a modification to the end plate 16 according to FIG. 10, radial noses 21 are provided that engage lateral recesses, not shown, of the filter housing, as is illustrated e.g. by means of the bottom part 3 according to FIGS. 2 a and 2 b. The recesses are sized such that with them, when contacted by the radial noses 21, a stop is formed so that by means of the remaining space a predetermined pretension can be produced when the non-return diaphragm contacts the sealing surface of the filter housing.

TECHNICAL UTILITY

The invention is, for example, usable in automotive technology, in particular in filter arrangements for liquids, in particular for oil or fuel. 

1.-11. (canceled)
 12. A filter arrangement for liquids, the filter arrangement comprising: a filter housing; a functional carrier arranged inside the filter housing; a cylindrical filter element inserted axially into the filter housing and defining an unfiltered side and a filtered side inside the filter housing; a non-return diaphragm secured within the filter housing, wherein the non-return diaphragm is arranged on the functional carrier so as to effect an axial and/or radial sealing action of the unfiltered side relative to the filtered side of the filter arrangement.
 13. The filter arrangement according to claim 12, wherein the non-return diaphragm is comprised of an elastomer and is attached to an axial projection of the functional carrier in such a way that the non-return diaphragm has a contact on sealing surfaces of the filter housing which contact is flexible within predetermined limits in an axial direction of the filter arrangement.
 14. The filter arrangement according to claim 13, wherein the axial projection of the functional carrier is sized such that the axial projection, upon contacting a step of the filter housing, provides a stop so that a length of the axial projection defines a predetermined pretension of the non-return diaphragm when resting against the sealing surfaces.
 15. The filter arrangement according to claim 12, wherein the functional carrier is a central tube that is metal-free and fixedly connected to the filter element, wherein the non-return diaphragm is fixedly attached to the central tube.
 16. The filter arrangement according to claim 12, wherein the functional carrier is a metal-free central tube that is fixedly mounted on the filter housing, wherein the non-return diaphragm is fixedly mounted on the central tube.
 17. The filter arrangement according to claim 12, wherein the functional carrier is an end plate connected fixedly to the filter element, wherein the non-return diaphragm is attached to the end plate.
 18. The filter arrangement according to claim 12, wherein the functional carrier is an end plate fixedly connected to the filter element, wherein the non-return diaphragm is attached to the end plate, wherein the end plate has radial noses that laterally engage matching recesses of the filter housing, wherein the recesses are sized such that, when the recesses are contacted by the radial noses, a stop is formed that defines a remaining space, wherein the remaining space provides a predetermined pretension when the non-return diaphragm contacts the sealing surface of the filter housing.
 19. The filter arrangement according to claim 12, wherein the functional carrier is an end plate connected with a snap-on connection to the filter element, wherein the non-return diaphragm is attached to the end plate, wherein radial snap-on noses of the end plate engage laterally intermediate spaces of folded filter webs of the filter element above an axial glued connection of the filter webs and, when doing so, extensions of the non-return diaphragm are radially and/or axially clamped between the functional carrier and the filter element for sealing purposes.
 20. The filter arrangement according to claim 12, wherein the non-return diaphragm is fixedly connected to the functional carrier by gluing, welding, or by a two-component method.
 21. The filter arrangement according to claim 12, wherein the non-return diaphragm is detachably connected to the functional carrier by coupling.
 22. The filter arrangement according to claim 12, wherein a liquid to be filtered is fuel or a lubricant for an internal combustion engine of a motor vehicle. 